Film element

ABSTRACT

A façade or roof structure in light weight construction having at least one film element made of at least one film or fabric layer which forms the outer walls of a weather-proof cavity which can be filled with a gas, at least one material layer for reducing the transmission of energy by radiation and/or for noise insulation being disposed on at least one side of the film or fabric layer. The material layer is almost totally enclosed by the film or fabric layer in order to protect against climatic conditions.

RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Patent Application Ser. No. 61/129,704 filed on Jul. 14, 2008, the entire contents of which are incorporated herein by reference.

SUMMARY

The present invention relates to a façade or roof structure in light weight construction having at least one film element made of at least one film or fabric layer which forms the outer walls of a weather-proof cavity which can be filled with a gas, at least one material layer being disposed on at least one side of the film or fabric layers in order to reduce the transmission of energy by radiation and/or to provide noise insulation.

In order to illustrate the different requirements due to the constant change in environmental conditions one should briefly discuss the physical rudiments of heat conveyance. Upon closer observation one can distinguish between three different basic processes in heat and energy transmission, transmission by heat conduction, transmission by convection and transmission by radiation.

With energy transmission by heat conduction, as a result of the temperature the individual atoms in a continuum are caused to vibrate about a rest position. The amplitude and frequency of the vibration are affected by the temperature, i.e., the higher the temperature, the greater the vibration amplitude that forms. The connection between the temperature and the energy content, i.e., the energy stored in the vibration, of a continuum is described by its heat capacity. If a continuum is heated up locally, the atoms vibrate here with a higher amplitude. This state spreads through the continuum, the adjacent atoms absorb energy and also begin to vibrate with a higher amplitude. The speed of propagation is described by the heat conductivity. The higher the heat conductivity, the more quickly the increased vibration amplitude spreads through the continuum. Due to this the amplitude at the original location decreases and it becomes cooler. The prevailing physical laws are the first and the second of Fick's laws. Characteristic of this type of energy transmission is the relatively slow progression because the stimulation only spreads slowly through the continuum.

A second type of energy transmission is the one brought about by convection. In the case of convection the heat is transmitted by the conveyance of material which is heated up in relation to the environment and by this material passing to the boundary of the latter. This type of energy conveyance takes place primarily in liquids and gases such as air, for example. The conveyance itself is described by the speed of the flowing media and by the heat storage capacity of the latter, and the passage of heat itself by means of the heat transmission which is dependent upon the robustness or viscosity of the flowing medium, the direction of outflow relative to the boundary, the coarseness of the boundary, and the form of the latter.

The form of energy conveyance for the subject matter of the invention is energy conveyance by means of radiation, or more precisely by means of electromagnetic waves. Unlike energy transmission by means of convection electromagnetic radiation does not need any medium. The conveyance can also take place in a vacuum. The most important radiation source for the earth is the sun. The radiation can be characterized by the wavelength, the amplitude and by the direction of vibration which is perpendicular to the direction of propagation of the wave.

The wavelength of the radiation is dependent upon the surface temperature of the radiating body, the amplitude of the number of radiating atoms or molecules and the chemical composition of the latter. In order to characterise the radiation the intensity is often specified as a function of the wavelength. For example, with a surface temperature of approx. 5,000° K. the sun has a maximum intensity in the range between 300 and 800 nm, i.e., precisely in the range of visible light. Shorter wave and longer wave portions are also present however. Overall the wavelength of the radiation of the sun ranges from 100 nm to approx. 2,500 nm. At a normal room temperature of approx. 300° K. bodies also radiate dependently upon their absorption capacity, and the maximum radiation is characteristically shifted in relation to the radiation of the sun. It is approx. 5 to 30 μm.

The radiation now interacts with all of the bodies in the form of reflection, transmission and absorption. The reflection is only dependent upon the surface properties, i.e., upon the color and coarseness of the material. Transmission and absorption are also dependent of course upon the thickness of the absorbing layer.

Bodies radiate according to their surface temperature and their surface properties, and so there is an interaction between all radiating surfaces in the surrounding area including the sun during the day and cold space at night. The two extremes of the sun during the day and cold space at night make it obvious that with external use of for example marquees or halls, there are two contrary conditions which also require different material properties.

With solid components, the outer layer is heated throughout the day by the radiation of the sun and by convection. The heat wave thus induced slowly propagates to the inside of the component. With solid components it is now possible to design the wall structures such that the heat wave only becomes effective within the component when it is night and correspondingly the heating effects no longer bring about radiation and convection. The heat insulating effect can be described disregarding the radiation affects due to the slow propagation of the heat wave. The slow heat wave and the storage capacity buffer the effect of the radiation together with the heat capacity of the component.

The situation with components which are formed from thin membranes is totally different from the situation just described. Here the outer layer is heated up by the radiation of the sun and convection. With a thickness of just approximately 1 mm the membrane is heated through the whole of its thickness after a very short time and consequently radiates both outwardly and inwardly. Therefore, the interior of the component is heated up in the shortest of times by radiation and by convection. There is therefore no slowing down or buffering as with solid components because due to the small thickness of the membrane the heat wave heats up the whole thickness of the membrane in the shortest of times. The spectrum of the effective radiation here is that of the sun, and the spectrum of the secondary radiation is determined by the temperature and the material of the membrane.

The situation of cold space at night is also very different. With a solid component the outwardly pointing layer is first of all cooled down by radiation towards the cold sky and by convection. In this way a heat wave is triggered from the inside to the outside which due to its low propagation speed, however, is absorbed by the thickness of the solid component being designed appropriately. Here too one can see a corresponding buffer effect.

With a membrane, however, cooling takes place by convection and radiation because, according to its temperature and its material properties, the membrane radiates towards the cold night sky which has a low radiation temperature, and cools down very quickly due to the small thickness. As a result the warm inside of the structure now radiates towards the cooled down membrane by means of which a constant conveyance of energy from the inside to the outside is brought about. These radiation effects are further amplified by convection.

It has therefore been proposed in various literature to provide the membrane with different coatings in order to reduce the conveyance of heat. These heat insulation and noise insulation materials for building construction are generally known. For example, DE 101 01 966 B4 discloses this type of heat insulation and noise insulation material which is in the form of a composite material with layers arranged over one another. The composite material has at least one metallized layer, at least one polyolefin layer, at least one air cushion layer. A disadvantage with this composite material, however, is that the outer layers of the composite material are exposed without any protection to the climatic conditions, and material becomes soiled, damaged or even worn out. Furthermore, it is very difficult with this type of composite material to create a complex which makes it possible to react to the different requirements arising from the constant change in environmental conditions. Moreover, this composite material is not translucent either.

The present invention provides a façade or roof structure which by effectively reducing the effects of radiation is less susceptible to any damage, is easier to clean and at the same time at least partially retains its translucence. Accordingly, the invention includes a material layer that is almost totally enclosed by the film or fabric layer in order to protect it against climatic conditions. In other words, the layers sensitive to climatic conditions are protected against environmental damage by being disposed inside the film element which is in particular cushion-like.

The film or fabric layers enclosing the at least one material layer can be chosen here such that on the one hand they do not experience any damage due to temperature fluctuations, humidity and soiling, and on the other hand are easy to clean, for example by simple washing, or are even designed to be self-cleaning, for example by a lotus-effect surface being chosen.

In one exemplary embodiment, the at least one material layer for reducing the transmission of heat by radiation and/or for noise insulation can be disposed on a side facing towards the cavity of at least one of the film elements. It can either be in direct contact with the film element, for example by means of vapour coating or sputtering. Other possibilities known in the prior art for applying this type of material layer to a film element, for example adhesive bonding, welding or similar, are also conceivable.

In order to form the material layers materials from the group comprising “low e layers” (layers with a very low emission), pigmented or non-pigmented ITO layers (indium tin oxide layers), pigmented or non-pigmented thin aluminium layers, pigmented or non-pigmented thin silver, gold or platinum layers, pigmented or non-pigmented laminated thin films with an ITO layer, or also combinations of the latter can be considered.

In order to achieve a specific reflectivity on or within the film element, the layer thicknesses of the material layers can be varied. Therefore, in one exemplary embodiment of the present invention layer thicknesses of between about 1 μm and about 100 μm, preferably between about 2 μm and about 75 μm, even more preferably between about 5 μm and about 50 μm, and in particular about 10 μm can be set.

If a number of material layers are disposed within the film element, it is also possible to choose the layer thickness differently depending on the requirement from material layer to material layer. Here, by choosing the layer thickness and/or the number of material layers within the cavity, the translucence can be matched to the conditions dependent upon the application. In this way it is possible to adjust the translucence specifically. The translucence of the film element can be chosen here to be between 2% and 75%, preferably between 10% and 60%, and in particular 50%.

In a further exemplary embodiment at least one further film element in the form of an intermediate layer is disposed within the cavity. In this way, on the one hand a number of film or fabric layers, optionally made of different materials and/or with different layer thicknesses, can be disposed within the cavity, and this increases the possibility of adjusting the noise insulation properties and the translucence of the film element.

On the other hand, by providing intermediate layers the stability of the film element vis-à-vis unwanted deformations, due for example to environment-induced stresses, can be improved. For this purpose the intermediate layers can be provided with cross members which also reduce or even totally prevent shifting or excessive deformation of the film or fabric layers in relation to one another.

The intermediate layer can be disposed in the cavity such that a number of sections or chambers are formed, and this makes is possible to set different pressures in the chamber sections formed by the intermediate layer(s). In this way on the one hand the rigidity of the heat insulation and/or the noise insulation material can be adjusted to match the application of the material, and on the other hand, by partial evacuation the noise insulation and also the convection specifically can be considerably improved or reduced.

A further improvement of the noise insulation properties can be achieved by the intermediate layer being formed by an acoustically absorbent material which is also disposed within the cavity.

In a further exemplary embodiment at least one intermediate layer is formed within the cavity as a solar foil, in particular as a printed thin solar foil.

Alternatively, at least one intermediate layer made of a translucent, self-supporting material strip is formed which is designed such that the heat conductivity and convection as well as the noise insulation properties can be adjusted by at least partial evacuation of the cavity. Due to the evacuation the noise can no longer move away without any obstruction because it is lacking the medium of air for this purpose. In comparison with the film elements the material strip is thicker in form here in order to prevent the layer from breaking during and after the evacuation.

A further possibility for adjusting the translucence or the heat insulation of the façade or roof structures can be achieved by at least one of the film elements being at least partially printed with an opaque material, in particular a printed thin solar foil. The translucence or heat insulation of the façade or roof structure can then consequently be adjusted by means of the print density. Here both outsides and insides of the film elements can be printed with the opaque material or the thin solar foil.

In one exemplary embodiment the intermediate layer is securely connected to the film element. Alternatively, the at least one intermediate layer disposed in the cavity can be drawn into the cavity, for example by means of an actuation mechanism, and be removable from said cavity again. This possibility for positioning the intermediate layer is advantageous when designing the intermediate layer as a solar foil because this type of film element can have two functions. If light is required in the marquee, e.g., because an event is to be held in the latter, the solar foil, which otherwise darkens the interior, can be removed from the film element, and so daylight can pass through the film element into the interior practically unhindered. If the marquee is not being used, the solar foil can be drawn into the film element once again and be used to generate power. Therefore, e.g. during the daytime power can be generated which is then required during an evening event in order to light the marquee. If one wishes to prevent excessive energy transmission due to radiation in relation to space at night, and so excessive heat loss occurring, the sides facing towards the marquee interior (and so in the example given above the rear side of the solar foil) can be provided with a radiation reflective material layer.

In order to be able to set positive pressure or negative pressure in the cavities or in the chamber sections, the film element according to the invention can be connected to an air generation unit.

In a further exemplary embodiment a filter or a drying apparatus is furthermore provided on the air generation unit. In this way on the one hand it becomes possible to filter the air and so remove particles of dirt from the air being supplied so as to prevent any damage to the sensitive material layers caused by this. On the other hand it is possible to dry and if appropriate to temper the air in order to prevent corrosion within the cavity and, when necessary, to provide a temperature barrier.

With regard to further advantageous embodiments of the present invention, reference is made to the claims and the following description of a number of exemplary embodiments by means of the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a cushion-type film element according to the invention with two material layers in order to reduce the transmission of energy by radiation and/or for noise insulation.

FIG. 2 illustrates a cushion-type film element according to the invention with an intermediate layer.

FIG. 3 illustrates a cushion-type film element according to the invention with a moveable intermediate layer.

FIG. 4 illustrates a cushion-type film element according to the invention with an intermediate layer and different pressures in the chambers formed by the intermediate layer.

FIG. 5 illustrates a cushion-type film element according to the invention with an intermediate layer made of a self-supporting material strip.

FIG. 6 illustrates a tent design with six film elements according to the invention.

DETAILED DESCRIPTION

Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless specified or limited otherwise, the terms “mounted,” “connected,” “supported,” and “coupled” and variations thereof are used broadly and encompass both direct and indirect mountings, connections, supports, and couplings.

FIG. 1 shows a film element 1 according to the invention for use in a façade or roof structure for light weight construction such as, for example, in mobile structures and in particular in tents.

The film element 1 has two film or fabric layers 2 which are arranged such that they form the outer walls of a weather-resistant cavity 3 which here is in the form of a cushion and which can be filled with gas.

Disposed within the cavity 3 formed by the film or fabric layers 2 are two material layers 4 for reducing the transmission of energy by means of radiation and/or for noise insulation. The material layers 4 have low e properties, i.e., they only have very low emission characteristics. In the cavity 3 formed by the film or fabric layers 2 there prevails a positive pressure, and this is why the film or fabric layers 2 curve outwards. To the side the film element 1 is respectively clamped into a binder 5 by means of which the film element 1 is either fixed directly in position with a support frame (not shown) or also, however, can be connected to a further film element 1.

In order to produce the film element 1 two film or fabric layers 2 are laid over one another and are welded at the edges such that a substantially parallel cavity 3 in the form of an air chamber is formed. In addition to the welding the film or fabric layers 2 can be provided with a support rib or cross member (not shown) in order to improve the dimensional stability of the film element 1. Further stiffening by means of support ribs distributed around the periphery of the film or fabric layers 2 are also conceivable.

In order to guarantee particularly simple cleaning of the film or fabric layers 2 or of the film element 1, these support ribs should wherever possible be disposed within the cavity 3. Due to the relatively smooth surface the film element 1 is easy to clean and more resistant to damage.

FIG. 2 shows a cushion-type film element 1 according to the invention according to FIG. 1 in which an intermediate layer 6 is disposed.

Disposed both on the insides of the film or fabric layers 2 forming the outer walls of the film element 1 and on both sides of the intermediate layer 6 are material layers 4 for reducing the transmission of energy by radiation and/or for noise insulation. In this exemplary embodiment the material layers 4 are vapour deposited. Of course it is also possible to place the material layers 4 onto the film or fabric layers 2 or the intermediate layer 6 in different ways known in the prior art, for example by sputtering, adhesively bonding over films, welding or similar.

In this exemplary embodiment the material layers 4 are all made from a low-e-coating the material thickness of which varies, however. The material layer 4 disposed on the upper film or fabric layer 2 has a layer thickness of approx. 4 μm, the material layer 4 disposed on the upwardly pointing side of the intermediate layer 6 has a layer thickness of approx. 2.5 μm, the material layer 4 disposed to the lower side of the intermediate layer 6 has a thickness of approximately 2 μm, and finally the material layer 4 on the film or fabric layer 2 disposed on the lower side has a layer thickness of approximately 3 μm.

In this exemplary embodiment all of the material layers 4 are in the form of low-e-coatings, but it is also conceivable to choose different material combinations of different materials such as, for example, pigmented or non-pigmented ITO layers, thin aluminium layers or thin silver, gold or platinum layers. Depending on the type, number and layer thickness of the material layer it is therefore possible to set a translucence of between 2% and 75% depending on the application.

FIG. 3 shows a film element 1 according to the invention with an intermediate layer 6 which can be disposed moveably by means of an actuation mechanism (not shown in detail) and which can be drawn into the cavity and removed from the latter again, as indicated by the arrows. In this way it is possible, depending on the desired application and area of application, for the reflection of the material layers 4 or the translucence of the latter to be adapted to the external conditions such as, for example, solar radiation or a cloudy sky.

FIG. 4 shows a cushion-type film element 1 according to the invention with a continuous intermediate layer 6 which divides the cavity 3 into two chambers 7. Both chambers are supplied separately by means of supply lines with a fluid or, as in this case, with gas. In the case shown in FIG. 4 the pressures of the respective gases are different so that certain shifting of the intermediate layer 6 and of the curvature of the film or fabric layers 2 and correspondingly different volumes occur.

In FIG. 5 a cushion-type film element 1 according to the invention is shown which has an intermediate layer 6 made, among other things, from a self-supporting material strip which is formed with a thickness comparable with the film elements 2 in order to prevent breakage of the layer during an evacuation. The material strip is designed such that, among other things, the heat conductivity and the convection as well as the noise insulation characteristics can be adjusted by at least partial evacuation of the cavity 3 in which the material strip, among other things, is disposed. Due to the evacuation the noise can no longer move away through the cushion without obstruction because the medium of air required by it for this is absent.

In this exemplary embodiment the intermediate layer 6 has a central opening 8 by means of which the two chamber sections 7 formed by the intermediate layer 6 are connected to one another. In this way it is possible for both chamber sections 7 to be filled by a single air generation unit with air or some other appropriate gas.

If the gas-tight cavity 3 is, for example, filled with air, the film element 1 forms a self-supporting air cushion which, in this exemplary embodiment, is aligned outwardly, which can be effected by the provision of further intermediate layers 6. It is therefore possible, for example, to effect the incline of the peripheral regions of the film element 1 by horizontal tangents between the film or fabric layers 2 and the intermediate layer 6, for example in order to guarantee simple drainage of rain water to all sides. If the outwardly aligned film or fabric layer 2 has a so-called lotus effect structure, even a type of self-cleaning surface of the façade or roof structure can be provided.

By designing the film element 1 as an air cushion an insulating effect, in particular against the transmission of heat, is achieved so that on the one hand with solar radiation less heating of the reconstructed space takes place, and on the other hand, with desired heating of the reconstructed space from the inside, one achieves a small amount of heat loss to the outside.

Of course it is also possible to fill individual film elements 1 or also chamber sections 7 with different gases. Therefore, for example, with tents which are to be used at night, it is advantageous to fill various cavities 3 with a halogen and so provide a light effect or illumination of the tent interior for a considerable time, or else fill the chambers 7 with an inert gas, a particularly light gas or some other special gas.

FIG. 6 shows a marquee design 10 with six film elements 1 according to the invention. The tent is substantially rectangular in form with side walls 10 a, 10 b, 10 c and 10 d and a roof 11 which lies substantially horizontally. The roof 11 of the tent comprises a number of film elements 1 which are disposed over one another and are connected to one another at their peripheral regions, in this exemplary embodiment being welded to one another. At the outer edges 12 of the film elements 1 of the roof 11 a circumferential welt 12 is provided by means of which the film elements 1 can be attached to the support structure 13 of the tent and can be clamped onto the latter. The film elements 1 are respectively made up of film or fabric layers 2, at least one of the film or fabric layers 2 being printed with an opaque material, here in the form of circles. The diameter of the circles determines the surface covered by the circles, and so the translucence and the brightness within the tent.

Various features and advantages of the invention are set forth in the following claims. 

1. A façade or roof structure in light weight construction having at least one film element made of at least one film or fabric layer which forms the outer walls of a weather-proof cavity which can be filled with a gas, at least one side of the film or fabric layer in direct contact with at least one material layer being coated in order to reduce the transmission of energy by radiation and/or to provide noise insulation, wherein the material layer is substantially enclosed by the film or fabric layer in order to protect it against climatic conditions.
 2. The façade or roof structure according to claim 1, wherein at least one material layer for reducing the transmission of energy by radiation and/or for noise insulation is disposed on a side facing towards the cavity of at least one of the film or fabric layers.
 3. The façade or roof structure according to claim 1, wherein the material layer has a layer thickness of between 1 μm and 100 μm, preferably between 2 μm and 75 μm, more preferably between 5 μm and 50 μm, and in particular 10 μm.
 4. The façade or roof structure according to claim 3, wherein by choosing the layer thickness of the material layers and/or the number of material layers within the cavity a translucence of between 2% and 75%, preferably between 10% and 60%, and in particular 50% can be set.
 5. The façade or roof structure according to claim 1, wherein the material for forming the material layers is chosen from the group comprising low e layers, pigmented or non-pigmented ITO layers (indium tin oxide layers), pigmented or non-pigmented thin aluminium layers, pigmented or non-pigmented thin silver, gold or platinum layers, pigmented or non-pigmented laminated thin films with an ITO layer, or also combinations of the latter.
 6. The façade or roof structure according to claim 1, wherein at least one further film or fabric layer in the form of an intermediate layer is disposed within the cavity.
 7. The façade or roof structure according to claim 6, wherein the at least one intermediate layer divides the cavity into a number of chamber sections such that different pressures can be set in the chamber sections formed by the intermediate layer(s).
 8. The façade or roof structure according to claim 6, wherein at least one intermediate layer is formed by an acoustically absorbent material which is disposed within the cavity.
 9. The façade or roof structure according to claim 6, wherein at least one intermediate layer is formed within the cavity as a solar foil, in particular as a thin solar foil printed onto at least one of the film or fabric layers.
 10. The façade or roof structure according to claim 6, wherein at least one intermediate layer is made of a translucent, self-supporting material strip which is designed such that the heat conductivity and/or the convection and/or the noise insulation properties can be adjusted by at least partial evacuation of the cavity.
 11. The façade or roof structure according to claim 6, wherein the at least one intermediate layer disposed in the cavity be drawn into the cavity by means of an actuation mechanism and be removed from it.
 12. The façade or roof structure according to claim 1, wherein at least one of the film or fabric layers is printed at least partially with an opaque material, in particular with a thin solar foil, the translucence and heat insulation of the façade or roof structure being adjustable by means of the print density.
 13. The façade or roof structure according to claim 1, wherein the film element can be connected to an air generation unit in order to set a positive or negative pressure in the cavity.
 14. The façade or roof structure according to claim 13, wherein the air generation unit has a filter and/or a drying apparatus in order to supply the cavity with humidity-reduced and/or filtered and, if required, tempered ambient air. 